Surgical stapling device with firing lockout mechanism

ABSTRACT

A surgical stapling device includes a tool assembly having an anvil and a cartridge assembly that are movable in relation to each other between open and clamped positions. The cartridge assembly includes a staple cartridge that can be replaced after each firing of the stapling device to facilitate reuse of the stapling device. The anvil includes a lockout mechanism that prevents operation of the stapling device when the staple cartridge has been previously fired. The lockout mechanism moves from a locked position to an unlocked position in response to movement of the tool assembly from the open position to the clamped position.

FIELD

The disclosure is directed to surgical stapling devices and, moreparticularly, to surgical stapling devices with lockout mechanisms toprevent firing of the stapling device with a spent staple cartridge.

BACKGROUND

Surgical stapling devices for simultaneously stapling and cutting tissueare well known in the art. Typically, these stapling devices include atool assembly and a drive assembly. The tool assembly includes an anvilassembly and a cartridge assembly. The cartridge assembly includes achannel member and a staple cartridge that includes a cartridge body, aknife, and an actuation sled. The drive assembly is movable in relationto the anvil and cartridge assemblies to advance the actuation sled andknife through the staple cartridge to move the tool assembly betweenopen and clamped positions, to eject staples from the staple cartridge,and cut tissue clamped between the anvil and cartridge assemblies. Afterthe stapling device is fired, the actuation sled remains in an advancedposition within the tool assembly.

In some stapling devices, the staple cartridge is removably receivedwithin the channel member of the cartridge assembly and is replaceableto facilitate reuse of the stapling device. In order to preventactuation of the tool assembly after the staples have been fired fromthe staple cartridge, the tool assembly may include a lock mechanismthat is movable from an unlocked position to a locked position intoengagement with the drive assembly when the sled is in its advancedposition to prevent readvancement of the drive assembly. In somestapling devices, the lock mechanism is movable to the unlocked positionin response to insertion of a new or unfired staple cartridge into thechannel member.

A continuing need exists for a lock mechanism of simple constructionthat can prevent advancement of a drive assembly of a stapling devicewhen a spent staple cartridge is positioned within the channel member ofthe cartridge assembly.

SUMMARY

This disclosure is directed to a surgical stapling device having a toolassembly that includes an anvil and a cartridge assembly that aremovable in relation to each other between open and clamped positions.The anvil supports a lock mechanism that includes a lock member thatmoves from a locked position to an unlocked position in response tomovement of the tool assembly from the open position to the clampedposition.

One aspect of the disclosure is directed to a surgical stapling deviceincluding an elongate body, a tool assembly, a lock mechanism, and adrive assembly. The elongate body has a proximal portion and a distalportion. The tool assembly is supported on the distal portion of theelongate body and includes a cartridge assembly and an anvil. Thecartridge assembly includes a channel member and a staple cartridge. Thestaple cartridge is removably received within the channel member andincludes a cartridge body, staples, and an actuation sled assemblyincluding an actuation sled. The actuation sled assembly is movablethrough the cartridge body between retracted and advanced positions. Theanvil includes a body that is coupled to the cartridge assembly suchthat the tool assembly is movable between open and clamped positions.The lock mechanism is supported on the anvil and includes a lock memberthat is rotatable between a locked position and an unlocked position inresponse to movement of the tool assembly from the open position to theclamped position. The drive assembly includes a clamp member that ismovable in relation to the tool assembly between retracted and advancedpositions. The lock member is positioned to prevent movement of theclamp member from the retracted position to the advanced position in thelocked position.

In aspects of the disclosure, the lock member is biased towards thelocked position.

In some aspects of the disclosure, the lock mechanism includes a biasingmember to urge the lock member towards the locked position.

In certain aspects of the disclosure, the biasing member includes a coilspring.

In aspects of the disclosure, the actuation sled assembly includes aknife that is supported on the actuation sled.

In some aspects of the disclosure, the lock member engages the actuationsled assembly when the actuation sled assembly is in its retractedposition to retain the lock member in the unlocked position.

In certain aspects of the disclosure, the lock member engages the knifeof the actuation sled assembly when the actuation sled assembly is inits retracted position to retain the lock member in the unlockedposition.

In aspects of the disclosure, the lock member includes a circular hubportion and the anvil body defines a recess having a cylindricalportion.

In some aspects of the disclosure, the circular hub portion of the lockmember is received within the cylindrical portion of the recess torotatably support the lock member on the anvil body.

In certain aspects of the disclosure, the lock mechanism includes a pinthat engages the lock member to retain the lock member within the recessin the anvil body.

In aspects of the disclosure, the lock member includes an arm and anabutment member.

In some aspects of the disclosure, the circular hub portion ispositioned on a distal portion of the arm and the abutment member ispositioned on a proximal portion of the arm.

In certain aspects of the disclosure, the abutment member has anabutment surface that engages the clamp member when the lock member isin the locked position.

In aspects of the disclosure, the lock member is molded from plastic.

In some aspects of the disclosure, the locked member is stamped fromsheet metal.

In certain aspects of the disclosure, the anvil body includes anoverhang that is positioned over the recess to retain the lock memberwithin the recess.

Another aspect of this disclosure is directed to an anvil assemblyincluding an anvil and a lock mechanism. The anvil includes an anvilbody having a staple forming surface defining staple forming pockets anda longitudinal slot. The staple forming pockets are positioned onopposite sides of the longitudinal slot. The lock mechanism is supportedon the anvil body and includes a lock member that is rotatable between alocked position and an unlocked position. In the locked position, thelock member extends at least partially across the longitudinal slot.

Other features of the disclosure will be appreciated from the followingdescription.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the disclosure are described herein below withreference to the drawings, wherein:

FIG. 1 is side perspective view of a surgical stapling device includinga tool assembly having a locking mechanism according to aspects of thedisclosure with the tool assembly in an open position;

FIG. 2 is an enlarged view of the indicated area of detail shown in FIG.2;

FIG. 3 is a side perspective view the tool assembly shown in FIG. 2 withthe tool assembly in a clamped position;

FIG. 4 is a side perspective view of a clamp member of a drive assemblyof the stapling device shown in FIG. 1;

FIG. 5 is a side perspective view of a knife and actuation sled of thetool assembly shown in FIG. 3;

FIG. 6 is a side perspective view of the clamp member, actuation sled,and knife shown in FIGS. 4 and 5 with the clamp member engaged with theactuation sled;

FIG. 7 is a perspective view of the anvil of the tool assembly shown inFIG. 3 with a lock mechanism secured to the anvil;

FIG. 8 is a perspective view of the anvil and lock mechanism shown inFIG. 7 with the lock mechanism separated from the anvil;

FIG. 9 is a side perspective view from a first side of a lock member ofthe lock mechanism shown in FIG. 8;

FIG. 10 is a side perspective view from a second side of the lock memberof the lock mechanism shown in FIG. 8;

FIG. 11 is a cross-sectional view taken along section line 11-11 of FIG.7;

FIG. 11A is a perspective view of another alternate version of the anviland lock mechanism of the tool assembly of the stapling device shown inFIG. 1;

FIG. 12 is a side perspective view of the clamp member, the actuationsled, and the lock mechanism of the tool assembly shown in FIG. 9 withthe lock mechanism in an unlocked position;

FIG. 13 is a plan view of a proximal portion of the tool assembly withan anvil body of the anvil removed and the lock mechanism in an unlockedposition;

FIG. 14 is a cross-sectional view taken along section line 14-14 of FIG.12;

FIG. 15 is a side perspective view of the clamp member, the actuationsled, and the lock mechanism of the tool assembly shown in FIG. 12 withthe lock mechanism in a locked position;

FIG. 16 is a cross-sectional view taken along section line 16-16 of FIG.15;

FIG. 17 is a perspective view of an alternate version of the anvil andlock mechanism of the tool assembly of the stapling device shown in FIG.1;

FIG. 18 is a perspective view of the anvil and lock mechanism shown inFIG. 17 with the lock mechanism separated from the anvil; and

FIG. 19 is a side perspective view of an alternate version of the lockmember of the lock mechanism shown in FIG. 9.

DETAILED DESCRIPTION

The disclosed stapling device will now be described in detail withreference to the drawings in which like reference numerals designateidentical or corresponding elements in each of the several views.However, it is to be understood that aspects of the disclosure aremerely exemplary of the disclosure and may be embodied in various forms.Well-known functions or constructions are not described in detail toavoid obscuring the disclosure in unnecessary detail. Therefore,specific structural and functional details disclosed herein are not tobe interpreted as limiting, but merely as a basis for the claims and asa representative basis for teaching one skilled in the art to variouslyemploy the disclosure in virtually any appropriately detailed structure.In addition, directional terms such as front, rear, upper, lower, top,bottom, distal, proximal, and similar terms are used to assist inunderstanding the description and are not intended to limit thedisclosure.

In this description, the term “proximal” is used generally to refer tothat portion of the device that is closer to a clinician, while the term“distal” is used generally to refer to that portion of the device thatis farther from the clinician. In addition, the term “clinician” is usedgenerally to refer to medical personnel including doctors, nurses, andsupport personnel.

The disclosed surgical stapling device includes a tool assembly and adrive assembly for actuating the tool assembly. The tool assemblyincludes an anvil and a cartridge assembly that are movable in relationto each other between open and clamped positions. The cartridge assemblyincludes a channel member and a staple cartridge that is releasablyreceived within the channel member and replaceable to facilitate reuseof the stapling device. The staple cartridge includes a cartridge body,and an actuation sled assembly which may include a knife. The driveassembly includes a clamp member that is movable through the cartridgebody from a retracted position to an advanced position. Movement of theclamp member from its retracted position to its advanced positionadvances the actuation sled assembly though the cartridge body to movethe tool assembly from the open position to the clamped position and toeject staples from the staple cartridge. The anvil supports a lockmechanism that forms an anvil assembly with the anvil. The lockmechanism includes a lock member that is movable from a locked positionto an unlocked position in response to movement of the tool assemblyfrom the open position to the clamped position. In the locked position,the lock mechanism obstructs movement of the drive assembly from itsretracted to its advanced position to prevent operation of the staplingdevice. FIGS. 1-3 illustrate a surgical stapling device according toaspects of the disclosure shown generally as stapling device 10 whichincludes a handle assembly 12, an elongate body 14, and a tool assembly100. The elongate body 14 defines a longitudinal axis “X” (FIG. 1). Thehandle assembly 12 includes a body 18 that defines a hand grip 18 a, aplurality of actuator buttons 20, a rotation knob 22, and anarticulation lever 24. The rotation knob 22 is rotatably supported on adistal portion of the body 18 of the handle assembly 12 and supports theelongate body 14 to facilitate rotation of the elongate body 14 and thetool assembly 100 in relation to the handle assembly 12 about thelongitudinal axis “X”. The actuator buttons 20 control operation of thevarious functions of the stapling device 10 including approximation,firing, and cutting. The articulation lever 24 is rotatably supported onthe rotation knob 22 and is pivotable to effect articulation of the toolassembly 100 in relation to the elongate body 14 about an axistransverse to the longitudinal axis “X” of the elongate body 14.Although the stapling device 10 is illustrated as an electricallypowered stapling device, it is envisioned that the disclosed toolassembly 100 would also be suitable for use with manually poweredsurgical stapling devices and robotically actuated stapling devices.U.S. Pat. No. 9,055,943 discloses a surgical stapling device including apowered handle assembly and U.S. Pat. No. 6,241,139 discloses a surgicalstapling device including a manually actuated handle assembly. U.S. Pat.No. 9,962,159 discloses a stapling device that is configured for usewith a robotic system.

FIGS. 2 and 3 illustrate the tool assembly 100 which includes an anvil102 and a cartridge assembly 104. The cartridge assembly 104 includes astaple cartridge 106 and a channel member 108 that receives the staplecartridge 106. In aspects of the disclosure, the staple cartridge 106 isreleasably supported within the channel member 108 and is replaceable tofacilitate reuse of the tool assembly 100. The staple cartridge 106includes a cartridge body 110, an actuation sled 112 (FIG. 5), and aplurality of staples 114 (FIG. 13). The cartridge body 110 defines acentral knife slot 116 and staple receiving pockets 118. In aspects ofthe disclosure, the staple receiving pockets 118 are aligned in rowspositioned on each side of the central knife slot 116. Although threerows of staple receiving pockets 118 are shown in FIG. 2 on each side ofthe central knife slot 116, it is envisioned that the cartridge body 110may define one or more rows of staple receiving pockets 118 on each sideof the central knife slot 116. Each of the staple receiving pockets 118receives a staple 114 (FIG. 13). Although not shown, the staplecartridge 104 also includes pushers that support the staples 114 and areengaged by the actuation sled 112 (FIG. 5) as the actuation sled 112 isadvanced through the cartridge body 110 to eject the staples 114 fromthe cartridge body 110. In aspects of the disclosure, the actuation sled112 includes angled cam surfaces 112 a (FIG. 5) that engage and lift thepushers (not shown) within the cartridge body 110 of the staplecartridge 104 to eject the staples 114 from the cartridge body 110.

FIGS. 4-6 illustrate the actuation sled 112 of the staple cartridge 106and a clamp member 152 of a drive assembly of the stapling device 10(FIG. 1). In aspects of the disclosure, the actuation sled 112 supportsa knife 120 to form an assembly that is movable through the cartridgebody 110 from a retracted position to an advanced position. The knife120 includes a longitudinal body portion 122 and a vertically positionedcutting member 124 that extends from the body 122 through the centralknife slot 116 (FIG. 2) in the cartridge body 110 towards the anvil 102.

FIGS. 7 and 8 illustrate the anvil 102 of the tool assembly 100 whichincludes an anvil body 130 that has a proximal portion and a distalportion. The distal portion of the anvil body 130 has a staple formingsurface 136 that defines staple forming pockets 136 a. The stapleforming surface 136 is movable into juxtaposed alignment with the staplecartridge 106 (FIG. 3) when the tool assembly 100 is moved from the openposition to the clamped position to position the staple forming pockets136 a in juxtaposed alignment with the staple receiving pockets 118(FIG. 2) of the staple cartridge 106. The anvil body 130 defines achannel 138 and a longitudinal slot 140 that communicates with thechannel 138. The channel 138 has a proximal portion that is defined byramped surfaces 142 that are positioned on each side of the longitudinalslot 140. The proximal portion of the anvil body 130 includes sideflanges 144 that define openings 146. Each of the openings 146 receivesa pivot member 148 (FIG. 3) to pivotably couple the anvil 102 to thechannel member 108 of the cartridge assembly 104.

The stapling device 10 (FIG. 1) includes a drive assembly including adrive screw 150 (FIG. 13) and the clamp member 152 (FIG. 4). As known inthe art, the drive screw 150 is axially fixed but rotatably supportedwithin the cartridge assembly 104.

FIGS. 4 and 6 illustrate the clamp member 152 which includes a body 154having a first beam 156, a second beam 158, and a central portion 160that interconnects the first beam 156 and the second beam 158. Thecentral portion 160 includes a vertical strut 162 and a hub 164. Thevertical strut 162 defines a distal stop surface 172 and has a first endthat is secured to the first beam 156 and a second end that is securedto a first side of the hub 164. The hub 164 has a second side that isconnected to the second beam 158 and defines a threaded through bore 166that receives the drive screw 150 (FIG. 13). When the drive screw 150 isrotated within the cartridge assembly 104, the clamp member 152 isdriven longitudinally along the drive screw 150 within the staplecartridge 106 between retracted and advanced positions.

The first beam 156 is received within the channel 138 (FIG. 8) definedwithin the anvil body 130 of the anvil 102. When the clamp member 152moves from its retracted position towards its advanced position, thefirst beam 156 of the clamp member 152 engages the ramped surfaces 142of the anvil body 130 to pivot the anvil 102 in relation to thecartridge assembly 104 from the open position to the clamped position.The first beam 156 of the clamp member 152 includes a distally extendingfinger 156 a that has a downwardly extending projection 170 that slidesalong the longitudinal slot 140 (FIG. 7) of the anvil 102 to push tissuefrom within the longitudinal slot 140.

The second beam 158 is positioned to move along an outer surface 108 a(FIG. 3) of the channel member 108 (FIG. 11). In aspects of thedisclosure, the outer surface 108 a of the channel member 108 defines agroove (not shown) that receives the second beam 158 to guide the secondbeam 158 along the channel member 108. Engagement of the first andsecond beams 156 and 158 with the anvil 102 and the cartridge assembly104, respectively, sets a maximum tissue gap between the staple formingsurface 136 of the anvil 102 and the staple cartridge 106 (FIG. 2) asthe clamp member 152 moves through the tool assembly 100.

When the staple cartridge 106 is received within the channel member 108of the cartridge assembly 104, the clamp member 152 is positionedproximally of and adjacent to the actuation sled 112. In this position,the cutting member 124 of the knife 120 is positioned adjacent to thedistal stop surface 172 (FIG. 6) of the vertical strut 162 of the clampmember 152.

FIGS. 7-11 illustrate a lock mechanism 180 of the tool assembly 100which includes a lock member 182, a biasing member 184, and a pin 186.The lock mechanism 180 is supported on the anvil body 130 of the anvil102 to form an anvil assembly. The lock member 182 includes a circularhub portion 188, an arm 190 that extends proximally from the hub portion188, an abutment member 192, and a biasing member seat 194. The lockmember 182 is received within a recess 196 (FIG. 8) defined in the anvilbody 130. The recess 196 in the anvil body 130 has a distal portion 196a that is cylindrical and receives the circular hub portion 188 of thelock member 182 to facilitate rotation of the lock member 182 within therecess 196. The anvil body 130 also defines a transverse through bore198 (FIG. 8) and a groove 200. The through bore 198 intersects therecess 196. The pin 186 is received within the through bore 198 andengages a flat 188 a (FIG. 9) on the distal portion of the circular hubportion 188 of the lock member 182 (FIG. 11) to retain a distal end ofthe lock member 182 within the recess 196 of the anvil body 130. Theanvil body 130 also includes an overhang 189 (FIG. 7) that extends overthe proximal portion of the lock member 182 to retain the proximal endof the lock member 182 within the recess 196 of the anvil body 130.

In an alternate version of the disclosure shown in FIG. 11A, the pin 186is replaced by a second overhang 189′ that is formed on the anvil body130′. The second overhang 189′ also retains the lock member 182′ withinthe recess 196′ of the anvil body 130′.

The lock member 182 includes a transverse blind bore 202 (FIG. 9) thatis aligned with the biasing member seat 192. The biasing member 184 ofthe lock mechanism 180 is received within the groove 200 (FIG. 8) in theanvil body 130 and extends into the blind bore 202 and into engagementwith the biasing member seat 192 of the lock member 182 to urge the lockmember 182 towards a locked position described in further detail below.In aspects of the disclosure, the biasing member 184 includes a coilspring although the use of a variety of different biasing members isenvisioned.

The abutment member 192 of the lock member 182 extends upwardly from thearm 190 of the lock member 182 and from the anvil body 130 (as viewed inFIG. 7) towards the cartridge assembly 104 (FIG. 3). The abutment member192 is positioned adjacent the longitudinal slot 140 (FIG. 8) of theanvil 102 and includes a tapered or angled engagement surface 206 and anabutment surface 208. The lock member 182 is rotatable about an axis “Z”(FIG. 12) defined by the circular hub portion 188 from an unlockedposition (FIG. 14) to a locked position (FIG. 16). In the lockedposition, the abutment member 192 extends at least partially across thelongitudinal slot 140 of the anvil 102.

FIGS. 12-14 illustrate the tool assembly 100 (FIG. 3) in the clampedposition with the lock mechanism 180 in the unlocked position. When anew staple cartridge 106 (FIG. 2), i.e., unfired, is positioned withinthe channel member 108 of the cartridge assembly 104 and the toolassembly 100 is moved to the clamped position, the staple formingsurface 136 (FIG. 8) of the anvil 102 moves into juxtaposed alignmentwith the staple cartridge 106. As the anvil 102 pivots in relation tothe staple cartridge 106 (FIG. 2), the angled engagement surface 206(FIG. 10) of the abutment 192 of the lock member 182 engages the cuttingmember 124 of the knife 120. This engagement rotates the lock member 182of the lock mechanism 180 about the pivot axis “Z” (FIG. 12) in thedirection of arrow “A” in FIG. 12 against the urging of the biasingmember 184 from the locked position (FIG. 16) to the unlocked position(FIG. 13). In the unlocked position, the lock member 182 is engaged withthe cutting member 124 of the knife 120 to retain the abutment surface208 of the abutment member 192 in a position outwardly of the distalstop surface 172 of the clamp member 152. In this position, the staplingdevice 10 (FIG. 1) can be fired.

FIGS. 15 and 16 illustrate the tool assembly 100 in the clamped positionand the lock mechanism 180 in the locked position. When the staplingdevice 10 (FIG. 1) is fired, the clamp member 152 is advanced throughthe tool assembly 100 from a retracted position to an advanced position.As the clamp member 152 moves through the tool assembly 100, the clampmember 152 abuts and advances the actuation sled 112 and the knife 120(which is supported on the actuation sled 112) through the staplecartridge 106. Since the actuation sled 112 is only in abuttingrelationship with the clamp member 152, when the clamp member 152 ismoved from the advanced position back to the retracted position, theactuation sled 112 (FIG. 12) and the knife 120 remain in the distal endof the staple cartridge 106. As such, after the stapling device 10(FIG. 1) is fired and the clamp member 152 is returned to the retractedposition, the cutting member 124 of the knife 120 is no longerpositioned to obstruct movement of the lock member 182 of the lockmechanism 180 from the unlocked position to the locked position. Thus,the lock member 182 is moved by the biasing member 184 from the unlockedposition (FIG. 14) to the locked position (FIG. 16) in which theabutment surface 208 of the lock member 182 is positioned in alignmentwith the distal stop surface 172 of the clamp member 152 to preventdistal movement (or readvancement) of the clamp member 152 within thestaple cartridge 106.

FIGS. 17 and 18 illustrate an alternative version of the lock mechanismshown generally as lock mechanism 280. The lock mechanism 280 issubstantially like lock mechanism 180 (FIG. 8) except that the pin 186(FIG. 16) is not included in the lock assembly 280 and the circular hubportion 188 of the lock member 182 (FIG. 9) is replaced with a pivotmember 288 (FIG. 18). In this version of the lock mechanism 280, thedistal portion of the lock member 282 defines a through bore 290 and thepivot member 288 includes a protrusion 292 that is fixedly receivedwithin the through bore 290. In aspects of the disclosure, the throughbore 290 and the protrusion 292 are not circular to prevent rotation ofthe protrusion 292 within the through bore 290. In some aspects of thedisclosure, the through bore 290 of the lock member 282 and theprotrusion 292 of the pivot member 288 have oval configurations. Thepivot member 288 also includes a head portion 294 (FIG. 18) and acircular hub portion 296. The circular hub portion 296 of the pivotmember 288 is rotatably received within the distal portion 196 a of therecess 196 in the anvil body 130. The recess 196 extends through theanvil body 130 such that the circular hub portion 296 is received withinthe distal portion 196 a of the recess 196. The head portion 294 of thepivot member 288 engages the outer surface of the anvil body 130 toprevent the pivot member 288 from passing through the anvil body 130.

The lock mechanism 280 also includes a biasing member 284 that is likebiasing member 184 of lock mechanism 180 (FIG. 14) to urge the lockmember 282 towards the locked position. The lock mechanism 280 functionsin a substantially similar manner to the lock mechanism 180 and will notbe described in further detail herein.

In aspects of the disclosure, the lock members 182, 282 of the lockmechanisms 180, 280 can be molded from a suitable material, e.g.,plastic. In an alternate version of the lock assembly, as shown in FIG.19, the lock member shown generally as lock member 382 can be stampedfrom sheet metal.

Each of the lock mechanisms disclosed is supported on the anvil of thetool assembly of the stapling device. By positioning the lock mechanismon the anvil, the lock mechanism remains in a locked position until thetool assembly is moved to the clamped position. Although each of thelock mechanisms is shown for use with a stapling device having a staplecartridge that includes a knife, it is envisioned that the lockmechanisms are also suitable for use with stapling devices that do notinclude a knife. In such devices, the lock members of the lockmechanisms would engage the actuation sled of the staple cartridge toretain the lock mechanism in the unlocked position prior to actuation ofthe stapling device.

Persons skilled in the art will understand that the devices and methodsspecifically described herein and illustrated in the accompanyingdrawings are non-limiting exemplary embodiments. It is envisioned thatthe elements and features illustrated or described in connection withone exemplary embodiment may be combined with the elements and featuresof another without departing from the scope of the disclosure. As well,one skilled in the art will appreciate further features and advantagesof the disclosure based on the above-described embodiments. Accordingly,the disclosure is not to be limited by what has been particularly shownand described, except as indicated by the appended claims.

What is claimed is:
 1. A surgical stapling device comprising: anelongate body having a proximal portion and a distal portion; a toolassembly supported on the distal portion of the elongate body, the toolassembly including: a cartridge assembly including a channel member anda staple cartridge, the staple cartridge removably received within thechannel member and including a cartridge body, staples, and an actuationsled assembly including an actuation sled, the actuation sled assemblymovable through the cartridge body between retracted and advancedpositions; an anvil including an anvil body that is coupled to thecartridge assembly such that the tool assembly is movable between openand clamped positions; and a lock mechanism supported on the anvil, thelock mechanism including a lock member that is rotatable between alocked position and an unlocked position in response to movement of thetool assembly from the open position to the clamped position; and adrive assembly including a clamp member, the clamp member movable inrelation to the tool assembly between retracted and advanced positions,wherein the lock member is positioned to prevent movement of the clampmember from the retracted position to the advanced position in thelocked position.
 2. The surgical stapling device of claim 1, wherein thelock member is biased towards the locked position.
 3. The surgicalstapling device of claim 2, wherein the lock mechanism includes abiasing member to urge the lock member towards the locked position. 4.The surgical stapling device of claim 3, wherein the biasing memberincludes a coil spring.
 5. The surgical stapling device of claim 3,wherein the actuation sled assembly includes a knife that is supportedon the actuation sled.
 6. The surgical stapling device of claim 5,wherein the lock member engages the actuation sled assembly when theactuation sled assembly is in its retracted position to retain the lockmember in the unlocked position.
 7. The surgical stapling device ofclaim 6, wherein the lock member engages the knife of the actuation sledassembly when the actuation sled assembly is in its retracted positionto retain the lock member in the unlocked position.
 8. The surgicalstapling device of claim 1, wherein the lock member includes a circularhub portion and the anvil body defines a recess having a cylindricalportion, the circular hub portion of the lock member received within thecylindrical portion of the recess to rotatably support the lock memberon the anvil body.
 9. The surgical stapling device of claim 8, whereinthe lock mechanism further includes a pin, the pin engaging the lockmember to retain the lock member within the recess in the anvil body.10. The surgical stapling device of claim 8, wherein the lock memberincludes an arm and an abutment member, the circular hub portionpositioned on a distal portion of the arm and the abutment memberpositioned on a proximal portion of the arm.
 11. The surgical staplingdevice of claim 10, wherein the abutment member has an abutment surfacethat engages the clamp member when the lock member is in the lockedposition.
 12. The surgical stapling device of claim 11, wherein the lockmember is molded from plastic.
 13. The surgical stapling device of claim11, wherein the lock member is stamped from sheet metal.
 14. Thesurgical stapling device of claim 9, wherein the anvil body includes anoverhang that is positioned over the recess to retain the lock memberwithin the recess.
 15. An anvil assembly comprising: an anvil includingan anvil body having a staple forming surface defining staple formingpockets and a longitudinal slot, the staple forming pockets positionedon opposite sides of the longitudinal slot; and a lock mechanismsupported on the anvil body, the lockout mechanism including a lockmember that is rotatable between a locked position and an unlockedposition, wherein in the locked position, the lock member extends atleast partially across the longitudinal slot.
 16. The anvil assembly ofclaim 15, wherein the lock mechanism includes a biasing member that ispositioned to urge the lock member to the locked position.
 17. The anvilassembly of claim 16, wherein the lock member includes a circular hubportion and the anvil body defines a recess having a cylindricalportion, the circular hub portion of the lock member received within thecylindrical portion of the recess to rotatably support the lock memberon the anvil body.
 18. The anvil assembly of claim 17, wherein the lockmechanism further includes a pin, the pin engaging the lock member toretain the lock member within the recess in the anvil body.
 19. Theanvil assembly of claim 17, wherein the lock member includes an arm andan abutment member, the circular hub portion positioned on a distalportion of the arm and the abutment member positioned on a proximalportion of the arm.
 20. The anvil assembly of claim 15, wherein thelocked member is stamped from sheet metal.